Somewhere off Japan, a 40-foot buoy is bobbing and weaving in the ocean, dancing with the waves to generate its own electricity.

As it slowly gyrates, a floating platform heaves up and down, rotating an internal power generator that can feed up to 150 kilowatt-hours of electric power into a large battery, which can charge an autonomous underwater vehicle much like a Tesla charging station refuels a car.

Its owner, New Jersey-based Ocean Power Technologies, parked an identical giant yellow buoy just outside the NRG Center in Houston this week, hoping to strike up business with oil companies at the Offshore Technology Conference.

Before it found its way to Houston, the U.S. Navy had deployed the buoy half a dozen times off New Jersey, in tests designed to extend the range of its coastal surveillance. The buoy powered high-frequency radar and sonar technology that probes the ocean for hidden vessels, on the ocean's surface and below it.

"Unmanned underwater vehicles can be armed with bad stuff and could be sent 50 miles away from the U.S. coast with no way to detect them," said Mike Mekhiche, executive vice president at Ocean Power Technologies. "You could deploy this thing 200 miles offshore, put all kinds of sensors on it, and have a cost-effective surveillance means to detect vehicles we can't detect today."

The U.S. Navy funded the first iteration of the buoy in 2009. The idea was that the radar and sonar sensors would collect data off New Jersey and send it to onshore stations. In theory, it could spot things like narco-submarines, narcotics-filled vessels that typically travel from South America.

Now, the renewable energy company is trying to commercialize the technology. The buoy could, for example, power subsea oil and gas equipment for three years without requiring any maintenance, or recharge AUVs - essentially, underwater drones - that monitor deep-sea drilling operations, Mekhiche said.

"Having data to make decisions is a huge advantage when you're dealing with offshore threats or expensive infrastructure," he said.

Energy reporter for the Houston Chronicle. Houston native. Former banking and finance reporter.

Prior to joining the Houston Chronicle, Collin Eaton covered the local banking and finance scene at the Houston Business Journal. Before that, he held internships at newspapers in Texas and Washington D.C., generally writing about business, money or higher education. He graduated from the University of Texas at Austin in 2011.